Acute episodes: are restrictive with minimal obstruction; reversible with time.
Chronic forms: restrictive findings; may respond to corticosteroids; obstructive component possible (bronchitis obliterans).
Chest radiograph
Acute forms: both interstitial and alveolar filling processes.
Chronic forms: tendency for interstitial/nodular pattern; volume loss.
Complications
Cor pulmonale, respiratory failure, bronchitis obliterans, irreversible obstructive lung disease: can be fatal during any phase of disease.
Differential diagnosis
Pulmonary mycotoxicosis (toxic pneu-monitis from massive inhalation of fungi).
Recurrent infectious pneumonia (especially viral and mycoplasmal).
Sarcoidosis.
Vasculitides.
Cryptogenic fibrosing alveolitis.
Histiocytosis.
Pulmonary hemosiderosis.
Pulmonary eosinophilia.
Asthma.
Allergic bronchopulmonary aspergillosis.
Pneumoconiosis.
Etiology
• Hypersensitivity pneumonitis (“extrinsic allergic alveolitis”) is an immunologically mediated disease in which the predomi-nant mechanism of lung injury involves cell-mediated (T-cell) mechanism(s).
Examples of causative allergens Bacteria
Thermophilic actinomycetes–contaminated air-conditioning and humidifier systems.
Contaminated hay or grains.
Moldy sugar cane.
Mushroom compost.
Bacillus subtilis–contaminated walls.
Streptomyces albus–contaminated fertilizer.
Fungi
Moldy grain, tobacco, compost (Aspergillus spp).
Cephalosporium–contaminated sewer water and air-conditioning system.
Moldy cork (Penicillium).
Pullularia–contaminated sauna water.
Puffball spores in moldy dwellings.
Moldy maple bark (Cryptostroma).
Insects
Sitophilus granorius–infested flour (wheat weevil).
Animal proteins
Serum proteins from urine (parrot, para-keet, dove, pigeon), droppings (pigeon), feathers (duck, chicken, turkey, pigeon), or pelts (rat, gerbil, other animals).
Organic chemicals
Workers who handle isocyanates.
Other
Pyrethrum insecticide.
Amebae-contaminated water (in humidifiers).
Hypersensitivity pneumonitis syndromes
Treatment
Lifestyle management
• Adjust environment to avoid specific trigger and any related allergens.
Pharmacologic treatment
• Administer systemic glucocorticoid for 10–14 days to manage acute or subacute presentations; chronic form may require prolonged, alternate day administration.
• Institute basic respiratory support depending on clinical status:
Oxygen.
Cough suppressant.
Bronchodilator.
Antipyretics.
Treatment aims To avoid allergen exposure.
To reverse acute symptoms.
To identify pulmonary function abnor-malities and monitor improvement.
To identify concurrent pulmonary inflammatory disease (eg, asthma).
Prognosis
Excellent if allergen exposure can be eliminated; occasionally, patients with chronic disease have poorly reversible disease and, rarely, continued progres-sion despite allergen avoidance.
Follow-up and management.
• Monitor pulmonary function.
• Manage side-effects of treatment.
• Monitor environmental exposures.
Other treatment options
• Inhaled glucocorticoids are not suffi-cient to reverse the inflammatory process, and the addition of this modali-ty will not permit continued exposure to allergen.
General references
Fink JN: Hypersensitivity pneumonitis. In Allergy, ed 2. Edited by Kaplan AP. Philadelphia:
WB Saunders Co.; 1997:531–541.
Pfaff JK,Taussig LM: Pulmonary disorders. In Immunologic Disorders in Infants and Children, ed 4. Edited by Stiehm ER. Philadelphia:WB Saunders Co.; 1996:659–696.
Hypertension
Diagnosis
Symptoms
• Many patients can be asymptomatic.
Headache, blurry vision, epistaxis, chest pain: are generalized symptoms associated with hypertension.
Drooling, inability to close eyes: Bell’s palsy.
Flushing, palpitations: associated with pheochromocytoma.
Weight gain or loss: renal insufficiency, acute glomerulonephritis.
Rash: systemic lupus erythematosus, Henoch-Shönlein purpura.
Signs
Unusual body habitus: thin, obese, growth failure, virilized, stigmata of Turner or Williams syndrome.
Skin lesions: café-au-lait spots, neurofibromas, rashes.
Moon facies: Cushing’s syndrome.
Hypertensive retinopathy: rare in children.
Congestive heart failure: crackles, gallop, hepatomegaly, jugular venous distention.
Abdominal mass: tumor or obstruction.
Abdominal bruit: renal artery stenosis.
Ambiguous or virilized genitalia: adrenal etiology.
Investigations
Blood pressures: should be obtained using an appropriate-sized cuff; the inflatable bladder should encircle the arm and cover 75% of the upper arm;
several measurements should be obtained in a relaxed setting; normative data by age and gender should be reviewed before labeling patients as hypertensive.
Lower-extremity BP less than upper-extremity BP: coarctation of the aorta.
Urinalysis: for hematuria, proteinuria, and casts in glomerulonephritis.
Serum electolytes, renal function studies, uric acid, and cholesterol: to assess renal function, other risk factors, and potential adrenal dysfunction.
Echocardiogram: the most sensitive measurement of end-organ changes in hypertensive children.
Renal ultrasound: to visualize anatomic anomalies and scarring.
The following studies should be considered if the history and physical examination suggest a secondary cause.
Voiding cystourethrogram/DMSA renal scan: to identify vesicoureteral reflux and reflux nephropathy.
24-hour urine for catecholamines and metanephrines, MIBG scan: for pheochromocytoma.
Plasma renin activity (peripheral), renal vein renin activity, magnetic resonance arteriography, and renal arteriography: although the first three studies can be considered for screening, the latter is the “gold standard” in diagnosing renal artery stenosis.
Complications
Congestive heart failure.
Renal failure.
Encephalopathy.
Retinopathy.
Differential diagnosis Inappropriate cuff size.
“White coat” hypertension.
Etiology
• Secondary causes of hypertension are more common the younger the child and the greater the blood pressure.
• Secondary causes include renal parenchymal disease, cystic kidney dis-ease, reflux nephropathy; renal artery stenosis secondary to fibromuscular dys-plasia, neurofibromatosis,Williams syn-drome; coarctation of the aorta;
pheochromocytoma, hyperthyroidism, hyperaldosteronism; corticosteroids, sympathomimetics, oral contraceptives.
Epidemiology
• The prevalence of hypertension in chil-dren has been reported from 1.2% to 13%, although less than 1% require med-ication.
• The rate of hypertension in black adults is greater than in whites, although differences in children are not seen until after age 12.
Hypertension
Treatment
Diet and lifestyle
• Mild primary hypertension can be managed without medication. Emphasis should be placed on weight reduction (assuming the patient is obese), increased exercise, and some degree of sodium restriction. Smoking should be discouraged.
• Adolescents with well-controlled hypertension may participate in competitive athletics if they do not have end-organ involvement.
Pharmacologic treatment
• Medications should be considered if nonpharmacologic therapy has failed or if end-organ changes are present.